‘Beautiful accident’ leads to advances in high pressure materials synthesis

Unexpected results from a neutron scattering experiment at the Department of Energy’s Oak Ridge National Laboratory could open a new pathway for the synthesis of novel materials and also help explain the formation of complex organic structures observed in interstellar space.

In a paper published in the journal Angewandte Chemie International Edition, the multi-institutional team of researchers, led by Haiyan Zheng from the Center for High Pressure Science and Technology Advanced Research in Beijing, formerly of the Carnegie Institution of Washington, discuss their discovery of using high pressures—rather than high temperatures—to initiate chemical reactions.

Their research will significantly improve scientists’ understanding of complex carbon structures and may offer clues to the formation of amino acids from nonbiological processes.

“This discovery was somewhat of a beautiful accident,” said Ilia Ivanov, a research scientist at the ORNL’s Center for Nanophase Materials Sciences, a Department of Energy Office of Science User Facility.

Ivanov explains that it all began during a neutron diffraction experiment at ORNL’s Spallation Neutron Source—also a DOE Office of Science User Facility. While performing a high-pressure polymerization experiment on the chemical compound acetonitrile (CH3CN) using the SNAP instrument, researchers detected the unexpected presence of ammonia. Ammonia is a colorless gas but has a very distinct odor that can be detected in even minute quantities.

“If you put acetonitrile under high pressures, you’ll bring molecules together and see it reacting with itself, and eventually, it forms either a solid yellowish polymer or, as we found out, a black, carbon-rich material,” Ivanov said.

Acetonitrile is one of a number of organic compounds that have been discovered in outer space and is thought to be implicated in the origins of simple amino acids, one of the basic molecules of life. In a cosmic event such as an asteroid collision, the pressures and temperatures generated can be very large, and in the presence of acetonitrile, could mimic the experiment the researchers conducted at SNAP.

The formation of the yellowish polymer was the expected result of the SNAP experiment, said SNAP instrument scientist Chris Tulk, but a surprise was just ahead.

“When the sample was depressurized and the pressure cell opened, ammonia was detected. It has a very distinct scent,” Tulk said. “We thought, ‘there shouldn’t be ammonia in this sample right now.’ So we started looking for what could have happened to first form, and then release, ammonia.”

The experimental researchers then collaborated with experts in advanced electron microscopy, materials science and computing to understand the mysterious results. Based on a combination of computer simulations and microscopy, they concluded that nitrogen had left the acetonitrile sample, resulting in an enriched carbon-based material.

“The carbon material that was left was imaged using our best electron microscopes,” Ivanov said. “It had onion-like layers—one shell of carbon sheet after another. So nitrogen went somewhere, but where did it go? It escaped in the form of ammonia gas.”

Because a temperature-based catalyst is usually required to convert a polymer into another material, this ability to cause a chemical reaction through pressure alone is unusual.

“I wanted to continue doing these experiments to determine how much we could control the structure of a carbon material through pressure, not temperature,” said Ivanov, comparing the experimental conditions with those found in household pressure cookers.

“In most cases, pressure cookers still use high temperatures to help foods cook thoroughly. But with our experiments, we’ve been able to use a sort of pressure cooking at room temperature, albeit at much higher pressures.”

While a pressure cooker operates at 0.1 megapascals, these experiments used much higher pressures—up to 23,000 megapascals, which corresponds to the pressure found 650 kilometers below the Earth’s surface at the boundary between its upper and lower mantle.

“This paper is truly exciting for us,” Tulk said. “Using this process with the addition of oxygen, possibly by the addition of carbon dioxide or water into the reactants, complex carbon structures similar to the kind we suspect throughout early formation of amino acids on Earth may be realized.”

The researchers note that cross-disciplinary expertise in neutron sciences and nanoscience, together with Energy Frontier Research in Extreme Environments (EFree) Center, made the research possible. EFree is a DOE Energy Frontier Research Center.

“One without the other seemed like a one-sided mission. Two aspects of research, structure and functionality, were brought together through the synergetic work. Through joint efforts like this, we continue to help users drive the discovery of new materials and new functionalities,” Ivanov said.

December 8, 2016 - Pioneering research at Oak Ridge National Laboratory—a facility founded in the 1940s as part of the Manhattan Project, which developed the atomic bomb—as well as government support of advanced manufacturing, has created a magnet that has lured ...

December 7, 2016 - With Piranha, Almeria Analytics can make sense of vast amounts of data in mere minutes. Credit: Oak Ridge National Laboratory. ORNL's wireless sensor network provides researchers with an accurate index of population density in half-hour increments.

December 7, 2016 - As part of an effort to develop drought-resistant food and bioenergy crops, scientists at the Department of Energy's Oak Ridge National Laboratory have uncovered the genetic and metabolic mechanisms that allow certain plants to conserve water and ...

December 6, 2016 - In his interview with me, his goal was to get me to see the value that Katherine Way brought to the situation that ultimately created ORINS and eventually the Oak Ridge National Laboratory. I was anxious to learn as I knew nothing about her. In my ...

December 6, 2016 - By The Oak Ridger. The recently discovered element 117 has been officially named "tennessine" in recognition of Tennessee's contributions to its discovery - including the efforts of the U.S. Department of Energy's Oak Ridge National Laboratory and its ...

December 2, 2016 - "In a developed market, you are competing with cheaper forms of conventional power generation, such as gas and also hydro. Energy storage costs still have some way to come down for a hybrid plant like Kennedy Energy Park to be competitive," he said.

ORNL is the largest science and energy national laboratory in the Department of Energy system by acreage. ORNL is located in Oak Ridge, Tennessee, near Knoxville. ORNL’s scientific programs focus on materials, neutron science, energy, high-performance computing, systems biology and national security.

ORNL partners with the state of Tennessee, universities and industries to solve challenges in energy, advanced materials, manufacturing, security and physics.

The laboratory is home to several of the world’s top supercomputers including the world’s second most powerful supercomputer ranked by the TOP500, Titan, and is a leading neutron science and nuclear energy research facility that includes the Spallation Neutron Source and High Flux Isotope Reactor. ORNL hosts the Titan supercomputer; the Center for Nanophase Materials Sciences, the BioEnergy Science Center, and the Consortium for Advanced Simulation of Light-Water Reactors.

the Department of Energy’s Oak Ridge National Laboratory.

A team led by Olga Ovchinnikova of ORNL’s Center for Nanophase Materials Sciences Division used a helium ion microscope, an atomic-scale “sandblaster,” on a layered ferroelectric surface of a bulk copper indium thiophosphate. The result, detailed in the journal ACS Applied Materials and Interfaces, is a surprising discovery of a material with tailored properties potentially useful for phones, photovoltaics, flexible electronics and screens.

She and colleague Alex Belianinov noted that while the helium ion microscope is typically used to cut and shape matter, they demonstrated that it can also be used to control ferroelectric domain distribution, enhance conductivity and grow nanostructures. Their work could establish a path to replace silicon as the choice for semiconductors in some applications.

“Everyone is looking for the next material – the thing that will replace silicon for transistors,” said Belianinov, the lead author. “2-D devices stand out as having low power consumption and being easier and less expensive to fabricate without requiring harsh chemicals that are potentially harmful to the environment.”

Reducing power consumption by using 2-D-based devices could be as significant as improving battery performance. “Imagine having a phone that you don’t have to recharge but once a month,” Ovchinnikova said.

December 2, 2016 - "In a developed market, you are competing with cheaper forms of conventional power generation, such as gas and also hydro. Energy storage costs still have some way to come down for a hybrid plant like Kennedy Energy Park to be competitive," he said.

December 1, 2016 - SEATTLE - When firefighter paramedics Morlon Malveaux and Mark Pedeferri learned that their powerhorse diesel ambulance was going to be traded for a gas-powered hybrid they were more than a little concerned. The two, who run a Medic One rig ...